Javascript : generate random number function and push into array

Question

I'm trying to push a random number of bunnies into a canvas from 1~10 in Javascript. However, the Math.random() method doesn't seem to be working. It just gives me one bunny. What am I doing wrong?

var field = [];

var randomNum = Math.floor(Math.random() * 10);

field.push(randomNum * new Bunny());

function Bunny() {
...
}

T.J. Crowder · Accepted Answer · 2016-06-11 08:49:26Z

3

It won't give you any bunnies at all. randomNum * new Bunny() will be NaN¹, because you're trying to multiply an object with a number.

If you want multiple bunnies, you have to create them, probably in a loop:

var field = [];

var randomNum = Math.floor(Math.random() * 10);
for (var n = 0; n < randomNum; ++n) {          // Loop
    field.push(new Bunny());                   // creating and pushing
}                                              // multiple bunnies

function Bunny() {
// ...
}

¹ Or a number, if you've overridden valueOf on Bunny.prototype, which seems unlikely.

answered Jun 11, 2016 at 8:49

T.J. Crowder

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4 Comments

Morteza Tourani Over a year ago

I think you should use 1 + Math.floor(Math.random() * 10)

T.J. Crowder Over a year ago

@mortezaT: Indeed, if the goal is to have between 1 and 10 bunnies (inclusive), yes, we'd want the +1. If the goal is to have between 0 and 9 bunnies (inclusive), then we wouldn't.

T.J. Crowder Over a year ago

@AmyChun: See mortezaT's comment above, you likely want +1 on the line generating the random number.

Amy Chun Over a year ago

@T.J.Crowder Yes, I've noticed that during updating my code. Thanks for the tip, guys!

Jerzyk · Accepted Answer · 2016-06-11 10:22:24Z

0

var field = [];

var randomNum = Math.floor(Math.random() * 10);

for (k=0; k<randomNum; k++)

{

field.push(new Bunny());

}

edited Jun 11, 2016 at 10:22

Jerzyk

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answered Jun 11, 2016 at 8:54

Mehmet SÖĞÜNMEZ

6056 silver badges13 bronze badges

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